Kia Niro shows the importance of wheels on FE

[RedDevil]

low profile helps FE, low sidewall hurts badly.

[JSH]

TireRack has pretty complete specs for tires

The OEM tire on the Niro FE is a Michelin Energy Saver in 205/60R16.
21 lbs / 6.5" Tread Width / 25.7" dia / 810 RPM

The OEM tire on the Niro Touring is a Michelin Primacy MXMR in 225/45R18
24 lbs / 7.6" Tread Width / 26.0" dia / 802 RPM


The drop in fuel economy doesn't surprise me at all. Upgrading to decent A/S tires in a slightly wider tread width on my Prius and Spark dropped the fuel economy about 10%

In the Prius I went from
Bridgestone Ecopia EP422 (185/65R15)
17 lbs / 6.4" Tread Width / 24.4" dia

to a Bridgestone Turanza Serenity Plus (195/65R15)
22 lbs / 7.0" Tread Width / 25.0" dia

They dropped the fuel economy from 50 mpg to 45 mpg but transformed the handling and wet weather performance.

[euromodder]

If you want a bigger overall diameter, use taller tyres, not bigger rims (= more weight)

Just went from 3% oversized 15" wheels with 185 tyres, to stock 14" steelies with 175 winter tyres
The poor sluggisch Gasdwarf (it's got all of 68 HP / 55 kW) instantly became far more nimble with the smaller tyres !

[euromodder]

Originally Posted by mpg_numbers_guy

Are there any other cars with such MPG discrepancies based on wheels alone?

Renault has a webpage which shows the effect of temperature and rim size on range, for its electric Zoe

Bigger rims = less range


But it's not all that clear cut, and it also depends on the tyres fitted

Summer = +3% diameter 185/60 on 6.0 x R15 , 13,7 kg, EU FE : B-rated tyre
Winter = regular diameter 175/65 on 5.5 x R14 , 12,0 kg, EU FE : C-rated tyre

And guess what ...




So the smaller, lighter, regular diameter winter tyre matches the "light" alloy, oversized tyres, despite being used in winter conditions, and despite its worse RR

[freebeard]

My Dasher has +1 alloys. I should pay attention, with 48hp it needs all the help it can get.